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Stick two CDs with water together.


- two old CDs, which you do not need anymore
- some water


Clean the old CDs, in order to erase the dust on the CD's surface. (Cover the table with a water-proofed bottom layer or do the experiment outside)

Take one of the CDs, place it horizontal and pour some water over the CD.

Cover half of the wet CD with the dry CD, press the two CDs together and make sure that no air bubbles are in between the CDs.



Water consists of many water-molecules, which stick together. Water-drops just exist, be cause of this effect. Imagine the small water-molecules would not stick together and the drop would dissolve. But it does not. Therefore every molecule sticks together with its neighbor-molecule. But the molecules at the surface of the drop have less neighbors than the molecules in the center of the drop. So they have free "capacity" to stick to any other material. When the surface of the material is smooth enough, the water-molecules can stick to this surface. This effect appears not only at CDs but also at wet windows, contact lenses etc. The scientific description of this is effect is adhesion.